The invention relates to a shoe-sole consisting at least partially of plastic.
The invention is further concerned with a method for making such a shoe-sole. As a plastic material for instance foamed polyurethane, soft-PVC, ethylene-vinyl-acetate or thermoplastic caoutchouc may be used.
It is already known to make shoe-soles from plastic, as from foamed polyurethane, because such shoe-soles prop the foot softly and elastically and cause an agreeable feeling during walking. The fixing of the uppers to such shoe-soles of hard foamed polyurethane has been accomplished heretofore by nailing, screwing or clipping whereby the uppers in general are fastened laterally on the shoe-sole. With this fixing method the fixing elements frequently pluck out so that then the uppers separate themselves from the sole.
For soles of soft foam of polyurethane it is already known to fasten the uppers to the sole with an adhesive. This procedure is very laborious and expensive whereby nevertheless a satisfactory connection between sole and uppers is not ensured.
It is an object of the present invention to provide a shoe-sole consisting at least partially of plastic with which a simple and secure fixing of the uppers is possible.
It is a further object of the invention to provide a shoe-sole consisting at least partially of plastic by which damaging of the shoe-sole during walking, particularly by the tension forces thereby exerted by the uppers to the shoe-sole, is avoided.
It is another object of the invention to provide a shoe-sole with which a connection between the shoe-sole and the uppers can be made in such a way that the connection has a certain elasticity taking bendings and twistings of the shoe-sole, as occurring during walking. This elasticity shall thereby suitably be adapted to the properties of the material of the sole.
A further object of the present invention is to form the shoe-sole in such a manner that the uppers may be fixed quickly and with less expenditure of work. Moreover, a good anchoring of the joint members within the shoe-sole shall be ensured.